The Orlando Interdenominational Ministerial Alliance is joining the war on drugs with a series of 15 religious services aimed at helping youngters get off and stay off narcotics.

''Regardless of what anybody else does, unless the church really gets involved, then we're always going to have a problem,'' said the Rev. Henry McKinnon, head of the committee handling the anti-drug push.

''If we don't start doing something instead of talking, we're always going to have the problem. We feel it's gotten to the point where we're depending on law enforcement to do the church's job. It's not law enforcement's responsibility to save people.''

The alliance consists of 35 predominantly black churches in Central Florida that take political and religious stands on issues affecting the community. McKinnon, pastor of Community Baptist Church in Orlando, said the crusade will have both a religious and anti-drug message.

''For some time, we have been praying and asking God to take the taste of drugs from people,'' he said. ''But we realized that even if the drugs left, the fellows still had a problem; they weren't saved. We realized that sin was still the root of the problem.''

The first week's services will be held at Orlando churches, starting with Carter Tabernacle C.M.E. Church Monday night, New St. Mark Free Methodist Church on Tuesday, Community Baptist on Wednesday and St. John's Baptist Church on Thursday. There will be no Friday program. All services will start at 7:30 p.m.

The Rev. Leroy Dennis, pastor of New St. Mark, said other churches will play host to services in succeeding weeks. The crusade will end Nov. 26 at Malone Memorial Institutional Church of God in Christ in Orlando.

''There will be praying, preaching, singing, teaching and testimonies and counseling at every service,'' Dennis said. ''There will be testimonies from former drug users and from kids who have never used drugs.

''We're going to try and use reverse peer pressure. If a kid who uses drugs can talk other kids into using it, then one who doesn't use drugs ought to be able to keep other kids off it.''

The Rev. Leonard Holt, president of the alliance and pastor of Carter Tabernacle, said the pastors felt that the crusade is a natural outreach of their church ministries.

''At a meeting that we had setting some priorities, we found that the drug issue was a problem as well as evangelizing so we just put the two together,'' Holt said.

''We're hoping this will be the start of something so that people in the community will know they can come to us for help and for counseling.''